upper petaluma river watershed flood control projectupper petaluma river watershed flood control...
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Upper Petaluma River Watershed Flood Control Project
Christy Kennedy Tim Harrison
Meeting Agenda
A. Greetings and Introduction B. Overview of the Scoping Study C. Issues and Needs within the Upper
Petaluma River Watershed D. Review of Draft Objectives E. Potential Project Concepts F. Small Group Break-Out Session G. Next Steps
Core Project Objectives
• Flood hazard reduction – Improve management of stormwater that
contributes, directly or indirectly, to reduced flood hazards.
• Groundwater recharge – Increase beneficial recharge of groundwater,
whether or not that recharged groundwater is directly accessible as water supply.
Project Schedule
Stakeholder input
May 2011
Aug 2011
Oct 2011
Sep 2011
Windsor
Santa Rosa
Rohnert Park Cotati
Petaluma
Sonoma
Sebastopol
Scoping Study – Three Watersheds
Zone 2A
Zone 2A Watershed Overview
• 87 square miles • 12 major tributaries • Includes incorporated City of Petaluma
and rural community of Penngrove • Localized climatic conditions (20 inches
of rain at the mouth of the River to 50 inches of rain along the northeastern boundary)
Key Project Purpose
• Develop a stormwater management/groundwater recharge project(s) that will provide regional flood hazard reduction and groundwater benefits within the Upper Petaluma River Watershed.
Flood Hazard Reduction
Groundwater Recharge
Projects considered as part of the Scoping Study
Planned Process – Phases of Work
Feasibility
Gaps Analysis
Alternatives Analysis
Design/ Construction
Predesign/ Permitting
Implementation
Funding
Visioning, Develop
Objectives
Concept Development
Scoping
Stakeholder Involvement
Issues Assessment
Overarching Issues – Similar to Other Watersheds – Objectives Definition/Prioritization – Watershed Understanding – Stakeholder Coordination – Project Integration – Regulatory Constraints – Funding Identification – Effective Communication
Watershed Issues - Flooding
Marin and Wiggins Creek Watershed
• 11.2 square miles • Elevation range 558 ft – 28 ft • Average rainfall 25-30 inches • Upper portions steep, lower portions flat
(meandering channels, lower velocity, siltation, vegetation overgrowth)
Marin Creek
Wilson Creek
Watershed Issues - Flooding
Downtown Penngrove Flooding
Erosion along Lichau Creek
Watershed Issues - Flooding
Denman Reach Terracing Project
Detention Basin at Lichau Creek
Petaluma Valley Groundwater Basin
• Petaluma Valley Basin – 46,000 acres • Stratigraphy - faulted, discontinuous • Well capacities relatively low • Water quality inadequate is some areas
for potable standards – High TDS – Iron, managenese – Nitrates
Groundwater Supply
• % of total supply from groundwater for City, 0-9%
• Estimated annual groundwater limit for City is 2000-3000 AF (past production ranges from 0-1,400 AFY)
• Pumping varies, but steadily increased from 2006
Reference: Petaluma 2005 UWMP
Increasing Use of Groundwater
0
200
400
600
800
1000
1200
1400
1600
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
City’s Historical Groundwater Pumping (1970-2009)
Acr
e-Fe
et
Groundwater Quality Issues
• Northwestern area – nitrates – Top 50 feet extending from surface affected* – Proposed projects should avoid mobilization
• Southeastern area – salinity – Seawater intrusion – Connate water from Sonoma Volcanics
* DWR Bulletin 118-4, 1982
Surface Water Quality Issues
• Diazinon (a pesticide) • Nutrients • Pathogens • Sediment • Trash • Nickel
Meeting Agenda
A. Greetings and Introduction B. Overview of the Scoping Study C. Issues and Needs within the Upper
Petaluma River Watershed D. Review of Draft Objectives E. Potential Project Concepts F. Small Group Break-Out Session G. Next Steps
Draft Core & Supporting Objectives
Flood Hazard Reduction Groundwater Recharge
Water Quality
Water Supply
System Sustain-ability
Ecosystem Agricult-ural Land
Open Space
Comm-unity
Benefits
Draft Core Objectives
Core Objectives Definition and Components
Flood Hazard Reduction Improve management of stormwater that contributes, directly or indirectly, to reduce flood hazards.
A. Manage up to a 100-year storm event B. Coordinate projects within and downstream
of project area C. Consider “green” methods
Groundwater Recharge Increase beneficial recharge of groundwater, whether or not that recharged groundwater is directly accessible as water supply.
A. Provide recharge B. Provide water supply offset from floods
Draft Supporting Objectives Supporting Objectives Definition and Components
Water Quality Protect or improve water quality of surface water and groundwater.
A. Help eliminate impaired water body designations
B. Provide adequate water quality to sustain aquatic life
C. Facilitate long-term operations & maintenance permitting
D. Avoid aquifer degradation E. Improve aquifer water quality
Water Supply Increase or improve water supply availability, reliability and flexibility for domestic, municipal, industrial, agricultural and environmental use.
A. Offset use of groundwater and potable surface water by utilizing storm flows
Draft Supporting Objectives
Supporting Objectives Definition and Components
System Sustainability Support energy and water efficiency and climatic change resiliency of water management systems and developed supplies; provide for channel stability and sedimentation control; and consider the long-term viability of implemented project and impact on affected systems.
A. Minimize use of imported energy at the project site
B. Ensure water is used efficiently C. Implement improvements to mitigate effects
of erosion and sedimentation D. Implement improvements that facilitate
permitting for long-term O&M
Draft Supporting Objectives
Supporting Objectives Definition and Components
Ecosystem Improve ecosystem function and/or enhance habitat, especially for listed species
A. Integrate environmental habitat requirements into project
B. Promote sustainable, native habitats where possible
C. Preserve and enhance stream buffers and riparian areas
D. Facilitate long-term O&M permitting
Agricultural Land Preserve agricultural land use A. Minimize use of agricultural lands B. Preserve and enhance agricultural lands
Draft Supporting Objectives
Supporting Objectives Definition and Components
Open Space Preserve and/or enhance open space. A. Minimize use of open space lands B. Preserve and enhance open space lands C. Restore degraded open space lands
Community Benefits Create and/or enhance recreation, public access, education, etc.
A. Provide educational opportunities B. Cooperate with local agencies to implement
recreational features C. Protect or enhance visual resources
Draft Core & Supporting Objectives
Flood Hazard Reduction Groundwater Recharge
Water Quality
Water Supply
System Sustain-ability
Ecosystem Agricult-ural Land
Open Space
Comm-unity
Benefits
Meeting Agenda
A. Greetings and Introduction B. Overview of the Scoping Study C. Issues and Needs within the Upper
Petaluma River Watershed D. Review of Draft Objectives E. Potential Project Concepts F. Small Group Break-Out Session G. Next Steps
Project Concepts- Multi-Benefit Approach
Stormwater Detention and Recharge Basin (In-Channel)
Off-Stream Detention Basin
Malibu Legacy Park – Recessed Detention Basin
Off-Stream Detention Basin
Malibu Legacy Park – Recessed Detention Basin
Underground Detention & Recharge Basin
Downey Discovery Sports Park - Detention with Infiltration
Managed Natural Floodplain
Small-Group Break Out Session
• 15 minutes • Discuss relative importance of supporting
project objectives • Provide input on project concepts
• Designate one person per table to report back to group
Project Schedule/Next Steps
Stakeholder input
May 2011
Aug 2011
Oct 2011
Sep 2011
Upper Petaluma River Watershed Flood Control Project
Christy Kennedy Tim Harrison